Super-Earth's Atmosphere Detected For The First Time - And It's Dry, Hot And Poisonous

For the first time ever, astronomers have been able to analyse the atmosphere of a super-Earth exoplanet – sadly, it’s dry as a bone.

Researchers have been searching for and cataloguing planets outside of our Solar System for many years, but finding out more about these distant worlds is now easy task. The analysis of nearby super-Earth 55 Cancri e was only possible using a brand new technique.

The team found that the planet, larger than Earth but smaller than the Solar System gas giants, has a dry atmosphere consisting mostly of hydrogen and helium, with no sign of any water vapour.

Although a watery super-Earth would have been even more amazing, the results from the team led by the University College London in the UK are still pretty exciting.

"This is a very exciting result because it's the first time that we have been able to find the spectral fingerprints that show the gases present in the atmosphere of a super-Earth," explained Angelos Tsiaras, a PhD student at UCL, in a statement. "The observations of 55 Cancri e's atmosphere suggest that the planet has managed to cling on to a significant amount of hydrogen and helium from the nebula from which it originally formed."

Tsiaras developed the analysis technique along with his colleagues Ingo Waldmann and Marco Rocchetto and turned it on 55 Cancri e because it’s just 40 light years from here, relatively close for an exoplanet.

They used the Wide Field Camera 3 on the Hubble Space Telescope to observe the planet, thought to be one of the most common types in our galaxy. The WFC3 was already used on two other super-Earths, but the spectral features of the worlds weren’t found.

55 Cancri e, however, orbits very close to its parent star, which allowed the researchers to pick up on its atmosphere. Of course, this also helps to explain why it’s so dry, since a year on the planet is just 18 hours and temperatures on the surface reach around 2000 degrees Celsius.

Adding to its inhospitable atmosphere are traces of hydrogen cyanide, an indicator that the world is carbon-rich.

"If the presence of hydrogen cyanide and other molecules is confirmed in a few years’ time by the next generation of infrared telescopes, it would support the theory that this planet is indeed carbon rich and a very exotic place," said Jonathan Tennyson of UCL.

"Although hydrogen cyanide, or prussic acid, is highly poisonous, so it is perhaps not a planet I would like to live on!"

The team figured all this out by processing images taken WFC3 through their analytic software. The observations were made by scanning the instrument very quickly across the planet’s bright parent star to create a number of spectra. This allowed the scientists to unpick the spectrum of 55 Cancri e from the light of its sun.

I'm a freelance science and technology journalist. I started my career in the Middle East's growing media sector as a reporter on Arabian Computer News, before putting in a couple of hectic years on the business desk of busy daily newspaper 7DAYS in Dubai during the global e...